Itinerant electron magnetism inCaRu1−xMnxO3 (0 ≤ x ≤ 0.5)

Abstract

The effect of Mn substitution in paramagnetic metalCaRuO3 was studiedby magnetization and neutron diffraction measurements. Development of ferromagnetic order is observedfor x≥0.2 inCaRu1−xMnxO3. For the samplewith x = 0.4, the Curietemperature of ∼160 K is obtained from the Arrott plot and the ratio of effective moment and saturation momentPeff/M(0) is estimatedto be ∼4.8. We further found that the magnetization is significantly suppressed with decreasing temperatureT below∼90 K. In the neutrondiffraction experiment at T = 15 K, we observed the evolution of a magnetic Bragg peak originating from the G-typeantiferromagnetic order as well as the ferromagnetic one. This strongly suggests that bothferromagnetic and antiferromagnetic states are coexistent with each other at low temperatures. In theM(T)02 againstT2 plot(here, M(T)0 is a spontaneous magnetization estimated from the Arrott plot),M(T)02 linearly increases withdecreasing T2 in theferromagnetic region between ∼90 and 160 K. The ferromagnetic properties of theCaRu1−xMnxO3 system(x≤0.5) are well explained in terms of spin fluctuation theory based on the itinerant electronmodel rather than the localized spin model.